Chapter 2

Sodium Carbonate Resources of the 

Eocene Green River Formation, Uinta 

Basin, Utah and Colorado

By Michael E. Brownfield, Ronald C. Johnson, and John R. Dyni

Chapter 2 of 7

Oil Shale Resources of the Uinta Basin, Utah and Colorado 

By U.S. Geological Survey Oil Shale Assessment Team

U.S. Geological Survey Digital Data Series DDS–69–BB

U.S. Department of the Interior

U.S. Geological Survey

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U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Brownfield, M.E., Johnson, R.C., and Dyni, J.R., Sodium carbonate resources of the Eocene Green River Formation, 

Uinta Basin, Utah and Colorado, 2010: U.S. Geological Survey Digital Data Series DDS–69–BB, chp. 2, 13 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Duchesne Sodium Carbonate and Halite Deposit....................................................................................1

Bird’s-nest Brine Field...................................................................................................................................5

Sodium Carbonate Mineral Resources....................................................................................................11

References Cited..........................................................................................................................................12

Figures

1. Map showing areal distribution of the Eocene Green River Formation in 

Green River, Piceance, and Uinta Basins, and the locations of five 

sodium carbonate deposits in Utah, Colorado, and Wyoming..............................................2

2. Map of Indian Canyon and Duchesne, Utah area showing inferred limits of bedded 

sodium carbonates and halite in the upper saline facies of the Parachute 

Creek Member of the Eocene Green River Formation, Uinta Basin, Utah ..........................3

3. Stratigraphic cross section showing saline mineral facies and underlying 

lacustrine rocks in the upper part of the Eocene Parachute Creek Member 

of the Eocene Green River Formation near Duchesne, Utah ................................................4

4. Generalized lithologic column showing bedded sodium-carbonate-mineral 

units in the Marine Minerals CH-2 borehole, Duchesne County, Utah................................6

5. Drill core containing saline zone units shown in figure 4. Recovered core 

from the Marine Minerals CH-2 borehole.................................................................................7

6. Drill core containing translucent crystals of eitelite in calcareous marlstone..................8

7. Drill core containing thin bands of sodium carbonate minerals in 

laminated calcareous marlstone ...............................................................................................8

8. Drill core containing small crystals of shortite in laminated calcareous marlstone ........9

9. Drill core containing eitelite and nahcolite crystals in calcareous marlstone ..................9

10. Drill core containing eitelite and nahcolite crystals in calcareous 

marlstone .....................................................................................................................................10

11. Map showing locations of selected wells drilled into the Bird’s-nest aquifer 

near Bonanza, Utah....................................................................................................................11

Table

1. Chemical analyses of the Bird’s-nest aquifer waters collected from 

U.S. Geological Survey core holes Coyote Wash-1 and Red Wash-1 ...............................12
Abstract

The Uinta Basin of northeastern Utah and Colorado 

contains one known deposit of bedded saline minerals in 

the Parachute Creek Member of the Eocene Green River 

Formation near the town of Duchesne, Utah and one sodiumcarbonate brine field, the Bird’s-nest zone of the Parachute 

Creek Member, which is within a confined aquifer in the 

eastern Uinta Basin near Bonanza, Utah. The Duchesne 

saline deposit contains eitelite (Na2CO3·MgCO3), nahcolite 

(NaHCO3), shortite (Na2Ca2(CO3)3), and wegscheiderite 

(Na5(CO3)(HCO3)3). 

The saline mineral deposit at Duchesne contains much 

smaller quantities of sodium carbonate minerals and is of 

limited extent when compared to the deposits of nahcolite in 

the Piceance Basin, Colorado and trona deposits in the Green 

River Basin, Wyoming. Because the bedded sodium carbonate 

mineral units at Duchesne are covered by thick overburden, 

conventional shaft mining would be technically unfeasible. 

However, if future drilling locates beds of sodium carbonate 

minerals of sufficient extent, thickness, and richness, they 

might be recovered by solution mining similar to the mining 

operation in the Piceance Basin.

Further study in the area of the Bird’s-nest brine field 

may reveal potential resources of sodium carbonate brines, but 

dissolved components, such as, chloride, sulfate, and fluoride 

might pose problems in their development.

Introduction

The Eocene Green River Formation contains lacustrine 

rocks with extensive oil shale beds and saline mineral 

deposits in parts of the Green River, Piceance, and Uinta 

Basins in Wyoming, Colorado, and Utah, respectively 

(fig. 1). The Green River Basin contains the largest known 

resource of sodium carbonate, consisting of bedded trona 

(Na2CO3·NaHCO3·2H2O), in southwestern Wyoming 

(Burnside and Culbertson, 1979; Dyni, 1996, 2005). The 

Piceance Basin, in northwestern Colorado, contains one of 

the largest known deposits of sodium bicarbonate, in the form 

of bedded and nodular nahcolite (NaHCO3) (Brownfield and 

others, 2010). Several companies currently mine beds of trona 

Sodium Carbonate Resources of the Eocene Green River 

Formation, Uinta Basin, Utah and Colorado

By Michael E. Brownfield, Ronald C. Johnson, and John R. Dyni

underground in Wyoming, and one company solution mines a 

thick bed of nahcolite in Colorado.

The Eocene Parachute Creek Member of the Green 

River Formation in the southwestern part of the Uinta Basin, 

Utah, near the town of Duchesne (fig. 1), consists of oil shale, 

marlstone, “mealstone,” dolomite, limestone, claystone, shale, 

siltstone, mudstone, and sandstone. Mealstone is defined as 

marlstone containing abundant calcite crystal pseudomorphs 

after shortite (Na2Ca2(CO3)3), which imparts a “mealy” appearance to the rock outcrops (Dyni, 1996). The Parachute Creek 

Member also contains the only deposit of bedded sodium 

carbonate yet known in the basin (Bradley, 1931; Erickson, 

1952; Milton and others, 1954; Dane, 1955; Milton, 1957; 

Dyni and others, 1985; Dyni, 1996). This deposit near Duchesne (fig. 1) consists of eitelite (Na2

Mg(CO3)

2

), shortite, and 

wegscheiderite (Na5(CO3)(HCO3)3). One sodium carbonate 

brine field has been delineated in the Parachute Creek Member, the Bird’s-nest zone or Bird’s-nest brine field, which is 

within a confined aquifer system in the eastern Uinta Basin 

near Bonanza, Utah (fig. 1).

Duchesne Sodium Carbonate and 

Halite Deposit

Fluvial and lacustrine rocks in the Parachute Creek 

Member of the Green River Formation in Indian Canyon near 

Duchesne contain illite, smectite (stevensite), quartz, sodium 

and potassium feldspar, calcite, and dolomite with lesser 

amounts of kaolinite, talc, analcime, and gypsum (Dyni and 

others, 1985; Dyni, 2002), which are typical components of 

the Parachute Creek Member. Sodium carbonate minerals, 

nahcolite, trona, wegscheiderite, eitelite, shortite, and halite 

have also been identified by many investigators (Milton and 

others, 1954; Dane, 1955; Milton, 1957; Dyni and others, 

1985; Dyni, 1996). The average shale-oil content of the saline 

mineral-bearing oil shale, measured in gallons per ton (GPT), 

in the Duchesne area is only about 5 GPT (Dyni, 2002).

Bradley (1931) reported abundant calcite crystal molds 

of a then-unknown salt in exposures of lacustrine beds of the 

Green River Formation in the eastern part of the Uinta Basin 

and in the northern part of the Piceance Creek Basin, resulting 

in the defining of several “saline phases” within the formation. 
2 Sodium Carbonate Resources of the Eocene Green River Formation, Uinta Basin, Utah and Colorado

Salt Lake City

Kemmerer

111°00' 107°00'

113°00'

43°00'

38°00'

Rifle

Grand

Junction

Anticline

Washakie

Basin

Green

River

Basin

Uinta

Basin

Duchesne

Piceance

Basin

EXPLANATION

Sodium carbonate

 brine

Sand

Wash

Basin

Bedded halite and sodium

 carbonate minerals

Bedded trona

Nahcolite

Black sodium

 carbonate water

41°00'

112°00'

Bonanza

Great Divide Basin

Vernal

Rock

Springs

Axial Basin

Anticline

Meeker

City or town

0 50 MILES

0 50 100 KILOMETERS

Uinta

Mountains Uplift

IDAHO

WYOMING

WYOMING

COLORADO

COLORADO

UTAH

UTAH

Figure 1. Areal distribution of the Eocene Green River Formation (shaded in yellow) in Green River, Piceance, 

and Uinta Basins, and the locations of five sodium carbonate deposits in Utah, Colorado, and Wyoming. The black 

sodium carbonate water contains water-soluble organic matter. Modified after Dyni (1996).

One of these “phases” included a sequence of lacustrine 

marlstone and shale in the upper part of the formation in 

Indian Canyon, near Duchesne (fig. 1), which Bradley (1931) 

designated as the “barren and saline facies.” Erickson (1952) 

reported the presence of the sodium carbonate mineral shortite 

in analyzed samples from core recovered from the Sun Oil 

Company borehole located in sec. 22, T. 9 S., R. 20 E., in the 

eastern part of the Uinta Basin. Milton and others (1954) and 

Milton (1957) also reported the mineral shortite and the new 

sodium carbonate mineral, eitelite (Na2Mg(CO3)2), from boreholes in the Uinta Basin, and Dane (1955) reported shortite 

and nahcolite, possibly bedded, in cuttings from the Carter Oil 

Company Joseph Smith No. 1 oil and gas well in sec. 16, T. 3 

S., R. 5 W. (figs. 2, 3).

Mapco Oil Company drilled the Shrine Hospital No. 1 

well in 1970 about 4 mi north of Duchesne (figs. 2, 3), and 

two intervals of core were recovered between the depths of 

4,140 to 4,147 ft and 4,165 to 4,252 ft. Samples of these saline 
Duchesne Sodium Carbonate and Halite Deposit 3

40°00'

Duchesne

Strawberry

River

Left Fork

Right Fork

SOWERS

CANYON

Indian Canyon

T.

2

S.

T.

3

S.

ANTELOPE

CREEK

T.

4

S.

T.

5

S.

R. 3 W.

R. 7 W. R. 6 W. R .5 W. R. 4 W.

Duchesne

River

40°15'

110°30'

110°15'

Starvation

Reservoir

Sodium

carbonate

spring

Location

map

Duchesne fault zone

Marine Minerals 2

UTAH

T.

6

S.

0 5 MILES

0 8 KILOMETERS

1,000

1,500

2,000

3,000

3,500

4,000

4,500

2,500

5,000

5,500

6,000

4,500

6,500

500

1 2

3

4

Figure 2. Indian Canyon and Duchesne, Utah area showing inferred limits of bedded sodium carbonates and 

halite in the upper saline facies of the Parachute Creek Member of the Eocene Green River Formation (dashed 

green line), Uinta Basin, Utah (Dyni, 1996), boreholes (shown as red circles), and line of stratigraphic section 

(heavy black line) shown on figure 3. Structure contours (shown in red) in feet, drawn with respect to a resistivitysonic log datum near the base of the saline facies (see fig. 3). Modified after Dyni and others (1985), and Dyni 

(1996).
1 Texaco Oil Co. Ute Tribal D–1 sec. 14, T. 3 S., R. 6 W. 2 Carter Oil Co. Joseph Smith 1 sec. 16, T. 3 S., R. 5 W. 3 Mapco Oil Co. Shrine Hospital No. 1 sec. 10, T. 3 S., R. 5 W. 4 Carter Oil Co

Willis Moon N

sec. 13, T. 4 S., R

3,0004,000

3,5004,0004,500

4,000

TD 4,246 ft

Resistivity-sonic geophysicallog marker (datum)

?

1,5002,0002,500

Horse Bench Sandstone Bed

Resistivity Caliper Sonic Resistivity Gamma

ray

Neutron Gamma

ray

Neutron Resistivity

3,500

WELL DEPTHS, IN FEET BELOW THE SURFACE ? ? Cored intervals Sodium carbonate and halite beds

Figure 3. Stratigraphic cross section showing saline mineral facies and underlying lacustrine rocks in the upper part of the Eocene Parachute of the Eocene Green River Formation near Duchesne, Utah. Numbers above each drill hole are keyed to line of stratigraphic section shown in figleaders point to possible beds of sodium carbonate minerals and halite interpreted from geophysical logs. Red line shown in Mapco Oil Co. Shrinwell is the location of a 6 ft tuff identified by Dyni and others (1985, his fig. 4). Modified after Dyni (1996).
Bird’s-nest Brine Field 5

beds from the deeper core were collected and analyzed, and 

consist mostly of halite (60–80 percent) with lesser amounts 

of wegscheiderite (20–40 percent) and minor amounts of marlstone (Dyni, 1996). The same cored interval also contained an 

additional six thin beds containing varied amounts of nahcolite, northupite (Na3

Mg(CO3)2Cl), trona, wegscheiderite, and 

eitelite interbedded with brown dolomitic marlstone (Dyni and 

others, 1985). The upper cored interval consisted of brown to 

gray dolomitic marlstone with no sodium carbonate minerals 

and halite detected (Dyni and others, 1985).

The Duchesne saline-mineral deposit was further tested 

by the Marine Minerals No. 2 core hole drilled in 1970, about 

one mile northwest of Duchesne (figs. 2, 4). A continuous core 

recovered from 50 to 2,857 ft in the borehole includes a salinemineral-rich zone (figs. 3, 5); Dyni, 1996) in the depth interval 

2,743–2,771 ft that contains a sequence of eitelite-bearing 

marly rocks overlain by brown marlstone, which was sampled 

and analyzed (fig. 4). Within this interval the total net thickness of eitelite is about 10.7 ft, including a 4.8-ft-thick bed 

at 2,757 ft that contains about 75 percent eitelite (figs. 4, 6) 

and beds containing thin bands of sodium carbonate minerals 

(fig. 7). In this section of the recovered core (2,743–2,771 ft), 

there is a 4.5-ft-thick tuff, which correlates with a tuff (6 ft 

thick) identified in the Mapco No. 1 Shrine Hospital core hole 

(fig. 3) by Dyni and others (1985) and Dyni (1996), and just 

above is a thin unit (0.6 ft) of laminated brown marlstone 

containing sodium carbonate minerals (fig. 4). Laminated 

marlstone containing small shortite crystals (fig. 8) was also 

identified in the lower part of the interval; thin beds of sodium 

carbonate minerals and halite were identified in the upper part 

(figs. 4, 9); and there is bitumen along fractures and bedding 

surfaces (fig. 10). The leaching of halite-rich zones that is 

visible on the outer surfaces of the recovered core (figs. 9, 10) 

was caused by circulating drilling fluids during the drilling 

process resulting in the sodium carbonate minerals forming 

thin resistant layers. The core from this well is stored at the 

U.S. Geological Survey’s Core Research Center, Lakewood, 

Colo.

The bedded sodium carbonate minerals and halite at 

Duchesne are in the lower part of the saline facies of the 

Green River Formation as defined by Bradley (1931). In 

Indian Canyon south of Duchesne (fig. 2), the saline facies is 

about 1,100 ft thick (Dyni and others, 1985; Dyni, 1996) and 

its base is marked by a 3-ft-thick tuff (identified as a coarsegrained tuffaceous sandstone by Bradley (1931, his pl. 9, base 

of column D). This tuff may be the same as the thick tuff bed 

noted in the Mapco Shrine Hospital No. 1 well (fig. 3) and in 

the Marine Minerals No. 2 core hole (fig. 4).

In Indian Canyon, the saline facies of the Parachute 

Creek Member of the Green River Formation consists of finegrained lacustrine rocks including cherty marlstone, claystone, 

“mealstone,” dolomite, limestone, and minor amounts of 

oil shale, sandstone, siltstone, and tuff. In the lower part of 

the saline facies, water-soluble sodium carbonate minerals 

and halite are particularly abundant (figs. 3, 4), and although 

the presence of bedded sodium carbonates and halite was 

encountered in core holes at Duchesne (figs. 3, 4), no solution breccias marking the former presence of such beds were 

observed along the outcrops in Indian Canyon (Dyni and others, 1985).

Underlying the saline facies is a 460- to 700-ft-thick 

unit—predominantly claystone, minor limestone, and numerous thin tuffs—which is devoid of sodium carbonate minerals 

and halite (Dyni, 1996). The unit is underlain by the Horse 

Bench Sandstone Bed (fig. 3) assigned to the Parachute Creek 

Member of the Green River Formation by Pipiringos (1978).

Published reports show that the bedded saline minerals at 

Duchesne can be traced on geophysical logs into other wells 

drilled in the area (Dyni and others, 1985, Dyni, 1996). Several beds of mixed halite and sodium carbonate minerals are 

shown on the cross section in figure 3. These beds range from 

2 to 19 ft in thickness (Dyni and others, 1985; Dyni, 1996). 

Other possible beds of sodium carbonate minerals and halite 

are indicated on Texaco Oil Co. Ute Tribal D–1 well in figure 

3. Bedded saline minerals underlie an inferred area of about 

86 mi2 just north of Duchesne (Dyni and others, 1985; Dyni, 

1996), but the area might be larger (fig. 2). Bryant and others 

(1989), for example, mapped the saline mineral facies about 

45 mi west of the Duchesne sodium carbonate mineral-bearing 

zone, in the same general area where Dyni and others (1985) 

reported saline-mineral cavities in lacustrine beds of mealstone and marlstone. Dyni and others (1985) also suggested 

that carbonate-bearing springs west of Duchesne (fig. 2) 

indicate that there are zones of sodium carbonate minerals 

at depth. These mapped occurrences of the saline facies and 

the presence of carbonate springs could add several hundred 

square miles to the saline facies characterized at Duchesne, 

Utah.

Bird’s-nest Brine Field

The Horse Bench Sandstone Bed was deposited over a 

wide area in the south-central part of Eocene Lake Uinta during a short regression during the deposition of the upper part 

of the Green River Formation. This unit, named by Bradley 

(1931) for exposures in the central part of the Uinta Basin 

southeast of Duchesne, Utah (fig. 1), is a ripple-bedded unit 

that lies 250 to 550 ft above the Mahogany zone (Bradley, 

1931; Cashion, 1995). The Horse Bench Sandstone consists of 

several gray to brown, fine-grained, calcareous, and micaceous 

sandstone beds; generally ranges in thickness from 10 to 50 ft; 

forms resistant benches in the central part of the basin; and 

grades northward toward the basin center into lacustrine oil 

shale rocks. During this regressive phase, the lake waters in 

the depocenter of the Uinta Basin became enriched in saline 

minerals, chiefly sodium bicarbonates (nahcolite) with lesser 

amounts of sodium chloride (Dyni, 1996). During early diagenesis, nahcolite was precipitated within the marly sediments 

as scattered crystals, nodules, and crystalline aggregates. A 

few thin beds of nahcolite may have also been deposited. Dyni 

(2008) reported that the Horse Bench Sandstone is 33 ft thick 
6 Sodium Carbonate Resources of the Eocene Green River Formation, Uinta Basin, Utah and Colorado DEPTH AND UNIT THICKNESS, IN FEET

5.7 Brown marlstone

Marly eitelite 2.1

Mixed halite and sodium-carbonate minerals

Marly eitelite

Marly sodium-carbonate salts

Mixed halite and sodium-carbonate

 minerals (see figs. 9 and 10)

0.4

0.3

0.5

2.9

3.5 Marly eitelite

Marlstone, some sodium-carbonate

 minerals (see fig. 7)

0.6

4.5 Tuff

Brown marlstone and eitelite

 crystals (see fig. 6)

4.8

0.7 Marlstone, some eitelite crystals

Marlstone, scattered shortite crystals

 (see fig. 8) 8.0

2,737.0

2,771.0

2,743.0

2,757.0

Depth

Unit

thickness

Figure 4. Generalized lithologic column showing bedded sodium-carbonate-mineral 

units and the halite-bearing unit in the Marine Minerals CH-2 borehole in the SE1⁄4 NW1⁄4 

sec. 34, T. 3 S., R. 5 W., Duchesne County, Utah. Modified after Dyni (1996).
Figure 5. Drill core containing saline zone units shown in figure 4. 

Recovered core from the Marine Minerals CH-2 borehole (depth 2,737 ft 

to 2,769.5 ft). Core sections: A, see figure 6; B, see figure 7; C, see figure 8; 

D, see figure 9; E, see figure 10. Core is located at the U.S. Geological 

Survey’s Core Research Center, Denver, Colo.

Bird’s-nest Brine Field 7
8 Sodium Carbonate Resources of the Eocene Green River Formation, Uinta Basin, Utah and Colorado

Figure 6. Drill core containing translucent crystals of eitelite in calcareous marlstone. Recovered 

core from the Marine Minerals CH-2 borehole (depth 2,758.4 ft to 2,759.2 ft). Arrow points to top 

of borehole. Note dime (0.7 inches in diameter) for scale. Core is located at the U.S. Geological 

Survey’s Core Research Center, Denver, Colo.

Figure 7. Drill core containing thin bands of sodium carbonate minerals in laminated 

calcareous marlstone. Recovered core from the Marine Minerals CH-2 borehole (depth 2,752 

ft to 2,752.5 ft). Arrow points to top of borehole. Note dime (0.7 inches in diameter) for scale. 

Core is located at the U.S. Geological Survey’s Core Research Center, Denver, Colo.
Figure 8. Drill core containing small crystals of shortite in laminated calcareous marlstone. 

Top of borehole towards the left. Recovered core from the Marine Minerals CH-2 borehole 

(depth 2,767.2 ft to 2,767.8 ft). Arrow points to top of borehole. Note dime (0.7 inches in 

diameter) for scale. Core is located at the U.S. Geological Survey’s Core Research Center, 

Denver, Colo.

Figure 9. Drill core containing 

eitelite and nahcolite crystals in 

calcareous marlstone. A, Leached 

core surface from circulating drilling 

fluids; B, Slabbed surface showing 

altered minerals (white coating) 

from sawing process. Recovered 

core from the Marine Minerals CH-2 

borehole (depth 2,745.5 ft to 2,746.2 

ft). Arrow points to top of borehole. 

Note dime (0.7 inches in diameter) 

for scale. Core is located at the U.S. 

Geological Survey’s Core Research 

Center, Denver, Colo.

A

B

Bird’s-nest Brine Field 9
10 Sodium Carbonate Resources of the Eocene Green River Formation, Uinta Basin, Utah and Colorado

A

B

Figure 10. Drill core containing eitelite and nahcolite crystals in calcareous marlstone. A, Leached 

core surface from circulating drilling fluids; B, Slabbed surface. Recovered core from the Marine 

Minerals CH-2 borehole (approximately 2,745.5 ft to 2,746.2 ft). Arrow points to top of borehole. Note 

dime (0.7 inches in diameter) for scale. Core is located at the U.S. Geological Survey’s Core Research 

Center, Denver, Colo.

and lies 538 ft above the Mahogany bed in Indian Canyon 

(fig. 2). It can be traced northward into the subsurface on 

resistivity logs, but it disappears farther to the north toward 

the depocenter of the Uinta Basin. The Horse Bench Sandstone appears to be correlative with the “Bird’s-nest zone,” an 

evaporite facies that crops out in the eastern part of the Uinta 

Basin.

On outcrop, the Bird’s-nest zone, about 75 ft thick, 

contains numerous cavities owing to dissolution of the nahcolite (NaHCO3

) nodules by surface waters (Cashion, 1967; 

1995). Groundwaters caused the dissolution, which resulted 

in forming a saline-rich aquifer in the upper part of the Green 

River Formation in an area of at least 250 mi2 in Uinta County 

(fig. 11), about 30 mi south and east of Vernal, Utah (Lindskov 

and Kimball, 1984; Dyni, 1996). At this location, the Bird’snest zone is approximately 300 ft above the Mahogany zone 

(Vanden Berg, 2009). The full extent and the lateral continuity of the aquifer have not been determined, and outcrops 

have not been mapped in detail (Vanden Berg, 2008). In the 

southern part of the area, analyses of waters sampled from 

wells drilled on Federal lease tracts Ua and Ub indicate that 

the aquifer is only slightly to moderately saline, ranging from 

1,000 to 4,800 mg/L of total dissolved solids (fig. 11). However, much higher salinities were analyzed in the aquifer in 

two core holes drilled by the U.S. Geological Survey (USGS) 

northwest of the Federal lease tracts, the Coyote Wash-1 and 

the Red Wash-1 respectively (fig. 11). Chemical analyses of 

the saline waters collected from the aquifer are listed in table 1 

from Scott and Pantea (1982a, b).

The Bird’s-nest aquifer provides a possible additional 

means for the disposal of large volumes of saline waters from 

oil and gas production in the Uinta Basin as current waterdisposal wells are reaching capacity (Vanden Berg, 2008, 

2009). Research by the Utah Geological Survey indicates that 

water movement within the aquifer might be controlled by 

fractures and gilsonite veins creating possible compartments 
Sodium Carbonate Mineral Resources 11

R. 22 E. R. 23 E. R. 24 E.

White

River

39°52'30"

40°07'30"

109°30'00" 109°07'30"

84

99

1.0

1.4

1.4

1.8

1.9

2.6

2.8

2.6

4.8 4.3

3.5

4.3

Federal oil shale

tracts Ua-Ub

Bonanza

T.

8

S.

T.

9

S.

T.

10

S.

Red Wash-1

Coyote Wash-1

0

4

5 MILES

8 KILOMETERS

45

Figure 11. Locations of selected wells drilled into the Bird’s-nest aquifer near Bonanza, 

Utah. Numbers indicate total dissolved solids in grams/liter (from Lindskov and Kimball, 

1984; and Scott and Pantea, 1982a, b). State highway 45 shown in brown. Modified after 

Dyni (1996).

in the aquifer. Investigation is needed especially to address 

the possibility that saline-water disposal into the Bird’s-nest 

aquifer might adversely affect the development of oil shale in 

the Uinta Basin.

Further study of the Bird’s-nest brine field in the vicinity of the USGS Coyote Wash and Red Wash core holes and 

adjacent areas (fig. 11) may reveal sodium carbonate waters 

enriched to levels that could potentially be exploited. Dissolved components in amounts that might cause difficulty in 

developing this resource include chloride, sulfate, and fluoride 

(Dyni, 1996).

Sodium Carbonate Mineral Resources

As noted earlier, the Uinta Basin contains at least one 

known deposit of bedded sodium carbonate minerals (Bradley, 1931; Erickson, 1952; Milton and others, 1954; Dane, 

1955; Milton, 1957), located near the town of Duchesne, 

Utah (fig. 1), and one sodium carbonate brine, the Birds-nest 

zone, which is within a confined aquifer in the eastern part 

of the basin near Bonanza, Utah (fig. 1). Sodium carbonate 

minerals identified in the Parachute Creek Member of the 

Green River Formation within the Duchesne deposit that may 

have economic potential are eitelite (Na2CO3·MgCO3), shortite 

(Na2Ca2(CO3)3) (fig. 6), and wegscheiderite 

(Na5(CO3)(HCO3)3).

Published data imply that the saline-mineral facies at 

Duchesne, Utah contain much smaller quantities of sodium 

carbonate minerals than the deposits of nahcolite in the 

Piceance Basin, Colorado and the trona deposits in the Green 

River Basin, Wyoming (Beard and others, 1974; Dyni, 1974; 

Burnside and Culbertson, 1979; Brownfield and others, 2010). 

Because the bedded sodium carbonate mineral-bearing units 

at Duchesne are deep, shaft mining would not appear to be 

economical. However, if future drilling encounters beds of 

sodium carbonate minerals of sufficient thickness and richness, they might be recovered by solution mining similar to 

the mining operation in the Piceance Basin (Brownfield and 

others, 2010). 
12 Sodium Carbonate Resources of the Eocene Green River Formation, Uinta Basin, Utah and Colorado

Table 1. Chemical analyses of the Bird’s-nest aquifer waters collected from U.S. Geological Survey core holes Coyote 

Wash-1 and Red Wash-1.

[Other ions in concentrations of less than 1 mg/L: As, Ba, Cr, Fe, Li, Mn, Hg, and Zn. See Scott and Pantea (1982a, b) for additional analytical 

details. L/min, liters per minute; mg/L, milligrams per liter; gal/min, gallons per minute; m, meters; na, not analyzed]

Core hole name Coyote Wash-1 Red Wash -1

Location SE1⁄4 NE1⁄4 sec. 22, T. 9 S., R. 23 E. SE1⁄4 NW1⁄4 sec. 1, T. 9 S., R. 22 E.

Thickness of aquifer (ft) 65 (19.8 m) 80 (24.4 m)

Depth to top of aquifer (ft) 1,739 (530 m) 2,021 (616 m)

Sample depth (ft) 1,746 (532 m) 2,021 (616 m)

Rock matrix Oil shale Oil shale

Yield (gals/min) 700 (2,650 L/min) 700–900 (2,650–3,400 L/min)

Chemical composition (mg/L)

Cl-1 3,100 650

F- 26 450

SO4-2 7,400 3,500

(HCO3

-1/CO3-2)1 13,130 13,890

B 180 240

Na+1 34,000 41,000

K+1 39 60

Ca+2 3 <1

Mg+2 1 0.2

SiO2 <2 <2

Organic carbon, dissolved na 60

pH 9.5 9.5

Alkalinity (as CaCO3) 79,300 105,000

(Total dissolved solids)1 83,900 98,600

1

The sum of CO3+HCO3 and the amounts of total dissolved solids, which were not determined in the original analyses, were estimated by Scott R. 

Charlton, University of Colorado (Dyni, 1996).

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